A known-type apparatus for cutting and/or etching substantially planar articles, comprising a flat surface on which designs and/or writings are made, comprises an operating group bearing cutting and/or etching means, provided for cutting and/or etching predetermined portions of the flat surface of the article, and further bears optical means for detecting the position and orientation of the designs and/or writings reproduced on the articles.
The operating group is arranged above a work plane, on which the article is rested, and is mobile along the work plane.
The work plane comprises abutting elements, arranged on the upper surface; the operator, having placed the article resting on the work plane, positions it abuttingly against the abutting elements.
The optical means are constituted by a vision camera which is connected to a control panel; due to its closeness to the work plane, the vision camera has a rather limited visual field and generally is able to capture only a portion of the flat surface of the article.
Numerous items of data are entered into the control panel, among which: the dimensions of the article to be worked; the number of designs and/or writings present on the article; the arrangement of the designs and/or writings on the flat surface of the article; the position, with respect to a reference system used for moving the operating group, in which the article will be arranged when it is positioned abutting the abutting elements; the portions of the surface of the article to be cut and/or etched and the sequence with which the cutting and/or etching operations will be made on the portions of the surface of the article.
The operating group is piloted by the control panel towards the article; the control panel knows the position of the article, when it has been placed by the operator against the abutting elements, such that the vision camera takes images of portions of the flat surface in which the designs and/or writings are present.
The control panel analyses the images of the vision camera such as to precisely identify the position of each design and/or writing of the article with respect to the reference system used for the movement of the operating group; this means that the position of each design and/or writing is known with the precision necessary for correctly performing the cut and/or etching.
The operating group is then piloted by the control panel to cut and/or etch the portions to be cut and/or etched on the basis of the data read by the vision camera relating to the position and orientation of the designs and/or the writings.
The operator however has to correctly orientate the article when arranging it abutting against the abutting elements such that the control panel correctly interprets the data supplied by the vision camera; a wrong orientation of the article would in fact cause errors in the following cutting and/or etching stage, as a design and/or a writing might be mistaken for another and consequently the cut and/or etching would be erroneously performed.
Therefore the operator has to be trained in how to orientate each article in order to arrange it correctly abutting against the abutting elements, basing his judgment for example on distinctive geometrical elements of the flat surface of the article and/or the arrangement of the designs and/or the writings with respect to the abutting elements.
In the light of the above, there is a high degree of probability that the operator might commit errors of orientation during the stage of positioning the article abutting against the abutting elements, in particular when the change of type of article under production is changed, i.e. when the article to be positioned on the work plane abutting against the abutting elements has geometrical characteristics and/or an arrangement of the designs and/or writings which are different from that or those of the preceding article.